A motor vehicle airbag system, and in particular a passenger-side module, customarily includes a trough-shaped reaction canister closed at its ends by endplates. An inflator is mounted within the reaction canister. The inflator normally comprises a cylindrical ignition can having gas ports through its wall. The ignition can encloses a gas generant surrounded by a filtration medium. A folded airbag is enclosed within the reaction canister with its mouth arranged to receive the gases from the generant when activated by a crash sensor.
Most prior art inflators include generants that burn from the center outward. They might be, for example, in the form of stacked washer-like wafers having an igniter passing through the central hole. Alternatively, the generant might be in the form of pellets surrounding the igniter. Upon ignition, the gases which are produced exit through gaps between the wafers, through spaces around the pellets, or through gaps between generant sections. These arrangements have worked well in practice. However, the number of individual pieces, both of the generant and the reaction canister, have required expensive fabrication machinery and an undesirable amount of handling and assembly. As a result, the inflator has become the most expensive part of the airbag module. Accordingly it is a primary object of the present invention to provide an airbag module wherein the number of parts is substantially reduced. Another object is to substantially reduce the amount of labor required to assemble such a module. Other objects, features and advantages will become apparent from the following description and appended claims.